Posted on 09/05/2002 9:08:22 AM PDT by RightWhale
Scientists attempt to measure speed of gravity
UNIVERSITY OF MISSOURI NEWS RELEASE
Posted: September 4, 2002
Ever since Albert Einstein proposed the general theory of relativity in 1916, physicists worldwide have tested the theory's underlying principles. Whil some principles - such as the speed of light is a constant - have been proven, others have enot. Now, through a combination of modern technology, the alignment of a unique group of celestial bodies on Sept. 8, and an experiment conceived by a University of Missouri-Columbia physicist, one more of those principles might soon be proven.
"According to Einstein's theory, the speed of gravity is assumed to be equal to the speed of light," said Sergei Kopeikin, MU associate professor of physics and astronomy. "While there is indirect evidence this is true, the speed has never been measured directly, and that's what we're attempting to do in an experiment that will not be possible again for another decade."
The experiment will involve precisely measuring the angular distances between several quasars, celestial objects in distant galaxies that resemble stars. On Sept. 8, Jupiter will pass very close to the primary quasar. When it does, its gravity will cause the quasar's position in the sky to shift by a distance that depends on the speed of gravity. Kopeikin and Ed Fomalont, a radio astronomer with the National Science Foundation's National Radio Astronomy Observatory (NRAO), will use an observational technique they developed to compare the position of the primary quasar to the position of other quasars unaffected by Jupiter. Using their data, they hope to confirm the accuracy of Einstein's theory further.
Measurements will be made using the NRAO's Very Long Baseline Array (VLBA), a series of 10, 25-meter radio telescopes located from the Virgin Islands to Hawaii, and the 100-meter radio telescope in Effelsberg, Germany, which is operated by the Max Planck Institute for Radio Astronomy. "Results from recent VLBA test observations indicate we can reach the accuracy necessary to determine the speed of gravity if the experiment goes well," Fomalont said.
"Japanese and NASA scientists also will conduct the experiment independently using other telescopes around the world, so we'll be able to compare our findings," Kopeikin said. "We believe the general theory of relativity is correct and that the speed of gravity is equal to the speed of light."
"The techniques we've employed for this experiment can also be used to more precisely determine the position of other objects in space," Fomalont said. "With more exact positioning of satellites, we could improve telecommunications. Unmanned space navigation could also be improved, allowing us to explore the solar system more deliberately."
The scientists said final results from the experiment should be available in mid-November.
I think you nailed it.
Yes, and much more.
I would posit that it's apparent position in the sky and its position in the sky are the same thing, since "in the sky" is only a particular reference frame based on a particular observation point - that of within earth's atmosphere.
Why do work when I can sit around picking at nits? ;)
Shalom.
Speed of light is independent of the speed of the observer.
I'm sure this concept went over the author's head.
(steely)
I think they mean something like this:
If you have a [really] super-massive object in a box on the planet Jupiter, constrained so it cannot move and then somehow set it vibrating [send it into orbit around Jupiter,] how long will it take for the vibration to be detected at some distance [on earth] using only the pull of its gravity to measure the motion?
How Jupiter's gravity is going to effect a quasar is beyond me. Sure wish that had been explained in this article.
Well, while we're throwing unsupported theories around, what do you think about this:
There are no attractive forces in the universe. Matter has, as part of its intrinsic nature, energy constantly streaming out from it in all directions evenly when not near other matter. Since the distribution is even, the matter is not impacted. However, the presence of other matter causes this energy field to be unevenly distributed such that energy does not stream in the direction of the other matter. This uneven distribution causes the objects to move toward each other.
A similar concept applies to magnetism, and the strong and weak nuclear bonds.
Now that this energy field has been identified, it is an exercise for the student to devise and experiment to detect this field and fully describe its behavior.
The Nobel committee can FReepmail me if it needs to contact me.
Shalom.
Personally, I prefer the polarizable vacuum theory.
Even though quasars are certainly far outside the solar system and totally beyond any measureable effect from Jupiter's gravity, the light emitted from the quasar and passing near Jupiter to us on earth can be affected by Jupiter's gravity.
I think it's unsupported. However, you won't have to share your award - the Nobel prize is never awarded posthumously ;)
Tell that to Mr. Nobel... :-)
Southack's guess? Gravity bends light. Light doesn't bend gravity.
Ergo, gravity is a GREAT DEAL faster than light.
And if the assassination consisted of somebody kidnapping the target and dropping him/her from a tall building, the two topics could be said to be related...
Before they devote too much time to the above, why don't they finish deciding which is heavier, a pound of lead or a pound of feathers ;-)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.